package com.xsherl.leetcode.solution;

import com.xsherl.leetcode.utils.ArrayUtils;

public class UniquePaths2 {

    /**
     * dp[i][j] {
     *     0 , G[i][i] == 1
     *     dp[i - 1][j] + dp[i][j - 1], G[i][i] == 0
     * }
     */
    public int uniquePathsWithObstacles(int[][] obstacleGrid) {
        if (obstacleGrid[0][0] == 1){
            return 0;
        }
        int m = obstacleGrid.length, n = obstacleGrid[0].length;
        int[][] dp = new int[m][n];
        for (int i = 0; i < m && obstacleGrid[i][0] != 1; ++i){
            dp[i][0] = 1;
        }
        for (int j = 1; j < n && obstacleGrid[0][j] != 1; ++j){
            dp[0][j] = 1;
        }
        for (int i = 1; i < m; ++i){
            for (int j = 1; j < n; ++j){
                if (obstacleGrid[i][j] == 0){
                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
                } else {
                    dp[i][j] = 0;
                }
            }
        }
        return dp[m - 1][n - 1];
    }

    public static void main(String[] args) {
        int[][] ints = ArrayUtils.parseArray("" +
                "[[0,0,0],[0,1,0],[0,0,0]]" +
                "", int[].class);
        int i = new UniquePaths2().uniquePathsWithObstacles(ints);
        System.out.println(i);
    }
}
